vim-patch:9.0.1380: CTRL-X on 2**64 subtracts two (#22530)

Problem:    CTRL-X on 2**64 subtracts two. (James McCoy)
Solution:   Correct computation for large number. (closes vim/vim#12103)

https://github.com/vim/vim/commit/5fb78c3fa5c996c08a65431d698bd2c251eef5c7

Co-authored-by: Bram Moolenaar <Bram@vim.org>

1 files changed, 11 insertions, 1 deletions

diff --git a/src/nvim/charset.c b/src/nvim/charset.c
index bf18d110c0..b792ae5ece 100644
--- a/src/nvim/charset.c
+++ b/src/nvim/charset.c
@@ -1500,9 +1500,10 @@ bool vim_isblankline(char *lbuf)
 /// @param strict If true, fail if the number has unexpected trailing
 ///               alphanumeric chars: *len is set to 0 and nothing else is
 ///               returned.
+/// @param overflow When not NULL, set to true for overflow.
 void vim_str2nr(const char *const start, int *const prep, int *const len, const int what,
                 varnumber_T *const nptr, uvarnumber_T *const unptr, const int maxlen,
-                const bool strict)
+                const bool strict, bool *const overflow)
   FUNC_ATTR_NONNULL_ARG(1)
 {
   const char *ptr = start;
@@ -1626,6 +1627,9 @@ void vim_str2nr(const char *const start, int *const prep, int *const len, const
         un = (base) * un + digit; \
       } else { \
         un = UVARNUMBER_MAX; \
+        if (overflow != NULL) { \
+          *overflow = true; \
+        } \
       } \
       ptr++; \
     } \
@@ -1664,12 +1668,18 @@ vim_str2nr_proceed:
       // avoid ubsan error for overflow
       if (un > VARNUMBER_MAX) {
         *nptr = VARNUMBER_MIN;
+        if (overflow != NULL) {
+          *overflow = true;
+        }
       } else {
         *nptr = -(varnumber_T)un;
       }
     } else {
       if (un > VARNUMBER_MAX) {
         un = VARNUMBER_MAX;
+        if (overflow != NULL) {
+          *overflow = true;
+        }
       }
       *nptr = (varnumber_T)un;
     }